Selecting a distributable storage media and coding format for distributing copyrighted content has long presented a problem for copyright owners, namely that various objectives and criteria used in the selection process are, at least within the universe of currently available media and format, directly counter to one another.
To illustrate, MPG-3 is one well known coding scheme, and has many benefits such as high reproduction quality, easy translation from one medium to another, and ease of distribution. However, distributing content as MPG-3 files provides little, if any, practical and effective protection against copying. It has no such protection because copying an MPG file because as long the copying does not lose any bits each copy is identical to the original. Numerous copy-protect techniques for MPG-3 and equivalent coding schemes have been proposed, and attempted, but none have proved effective, practical and acceptable in the marketplace of wide-distribution media. For example, encryption may, at least theoretically, make copying more difficult, but it has inherent costs as well as inherent weaknesses. First, encryption makes playback more of a nuisance because specialized playback decoders, as well as reliable means of distributing playback authorization codes, are needed. Second, regardless of the strength of the encryption, a playback device must have a digital-to-analog converter (DAC), and the DAC must receive the decrypted playback data. Since the DAC of many playback devices is, or may be made accessible to skilled persons, the encryption is easily defeated.